Registering a custom ValueParamProvider in Jersey 2.27

Question

I realize that these are internal APIs, but if they're available internally why not make them usable by the less privileged masses, and they're also extremely useful. Even though these APIs were internal in Jersey 2.25 they could be used, and I'd like to upgrade my Jersey version without breaking my custom Jersey extensions.

It's certainly possible to extend ValueParamProvider in Jersey 2.27, but I no longer see a way to register that Provider along with it's triggering annotation. Looking at how Jersey does this for its own implementations, it now uses a BoostrapConfigurator, which seems to be internalized to such an extent that external implementations can't use the same methodology.

Maybe I'm wrong about that, and if someone has a clear description of how, that would be great. Otherwise, does anyone know of a method for doing the same thing?

This used to work...

ResourceConfig resourcceConfig = ...

resourceConfig.register(new AbstractBinder() {

    @Override
    protected void configure (){ 
      bind(MyParamValueFactoryProvider.class).to(ValueFactoryProvider.class).in(Singleton.class);
      bind(MyParamInjectionResolver.class).to(new TypeLiteral<InjectionResolver<EntityParam>>() {

      }).in(Singleton.class);
    }
  }
});

With appropriate implementations of AbstractValueFactoryProvider and ParamInjectionResolver.

Now it looks like you need to implement ValueParamProvider, which is easy enough, but I'm not sure how to register that properly with the Jersey framework anymore. Any help appreciated.

Answer 1

You don't need to use any BootstrapConfigurator. All you need to is add the services to the injector and they will be added later to the list of value providers.

To configure it, you can still use the AbstractBinder, but instead of the HK2 one, use the Jersey one. The ValueParamProvider can still be bound the same way, but for the InjectionResolver, you should make sure to implement not the HK2 resolver, but the Jersey one. Then instead of binding to TypeLiteral, bind to GenericType.

I just want to add that a misconception that people have when trying to implement parameter injection is that we also need an InjectResolver to use a custom annotation for the method parameter. This is not the case. The method parameter annotation is just a marker annotation that we should check inside ValueParamProvider#getValueProvider() method. An InjectResolver is only needed for non-method-parameter injections, for instance field and constructor injection. If you don't need that, then you don't need the InjectionResolver.

Below is a complete example using Jersey Test Framework. I didn't use an InjectionResolver, just to show that it's not needed.

import org.glassfish.jersey.internal.inject.AbstractBinder;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.server.model.Parameter;
import org.glassfish.jersey.server.spi.internal.ValueParamProvider;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;

import javax.inject.Singleton;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.client.Entity;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.core.Response;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.function.Function;

import static org.assertj.core.api.Assertions.assertThat;


public class ParamInjectTest extends JerseyTest {

    @Target({ElementType.PARAMETER, ElementType.FIELD})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface Auth {
    }

    private static class User {
        private String username;
        public User(String username) {
            this.username = username;
        }
        public String getUsername() {
            return this.username;
        }
    }

    public static class AuthValueParamProvider implements ValueParamProvider {

        @Override
        public Function<ContainerRequest, ?> getValueProvider(Parameter parameter) {
            if (parameter.getRawType().equals(User.class)
                    && parameter.isAnnotationPresent(Auth.class)) {
                return new UserParamProvider();
            }
            return null;
        }

        private class UserParamProvider implements Function<ContainerRequest, User> {
            @Override
            public User apply(ContainerRequest containerRequest) {
                return new User("Peeskillet");
            }
        }

        @Override
        public PriorityType getPriority() {
            return Priority.HIGH;
        }
    }

    public static class AuthFeature implements Feature {

        @Override
        public boolean configure(FeatureContext context) {
            context.register(new AbstractBinder() {
                @Override
                protected void configure() {
                    bind(AuthValueParamProvider.class)
                            .to(ValueParamProvider.class)
                            .in(Singleton.class);
                }
            });

            return true;
        }
    }

    @Path("test")
    @Consumes("text/plain")
    public static class TestResource {
        @POST
        @Produces("text/plain")
        public Response post(String text, @Auth User user) {
            return Response.ok(user.getUsername() + ":" + text).build();
        }
    }


    @Override
    public ResourceConfig configure() {
        return new ResourceConfig()
                .register(TestResource.class)
                .register(AuthFeature.class);
    }

    @Test
    public void testIt() {
        final Response response  = target("test")
                .request()
                .post(Entity.text("Test"));

        assertThat(response.getStatus()).isEqualTo(200);
        assertThat(response.readEntity(String.class)).isEqualTo("Peeskillet:Test");
    }
}

---

Another thing I'll mention is that in previous versions where you extended AbstractValueFactoryProvider and implemented a ParamInjectionResolver, most people did this to follow how Jersey implemented parameter injection while still allowing for other injection points (field and constructor). If you still want to use this pattern, you can.

Below is the AuthFeature from the above test refactored

public static class AuthFeature implements Feature {

    @Override
    public boolean configure(FeatureContext context) {
        InjectionManager im = InjectionManagerProvider.getInjectionManager(context);

        AuthValueParamProvider authProvider = new AuthValueParamProvider();

        im.register(Bindings.service(authProvider).to(ValueParamProvider.class));

        Provider<ContainerRequest> request = () -> {
            RequestProcessingContextReference reference = im.getInstance(RequestProcessingContextReference.class);
            return reference.get().request();
        };

        im.register(Bindings.injectionResolver(new ParamInjectionResolver<>(authProvider, Auth.class, request)));

        return true;
    }
}

I figured this stuff out just digging through the source. All this configuration I saw in the ValueParamProviderConfigurator. You don't need to implement your own ParamInjectionResolver. Jersey has a concrete class already that we can just use, as done in the feature above.

If you change the TestResource to inject by field, it should work now

@Path("test")
@Consumes("text/plain")
public static class TestResource {

    @Auth User user;

    @POST
    @Produces("text/plain")
    public Response post(String text) {
        return Response.ok(user.getUsername() + ":" + text).build();
    }
}